Catheter

ABSTRACT

For use in administering continual spinal anesthesia, a catheter for longitudinal movement within the lumen of a relatively large needle used to approach just about to the spinal column to the end of the catheter, a thin needle with a through opening is secured and a stylet is provided in the catheter to advance the small needle relative to the large needle to pierce the wall of the spinal column in a relatively fine opening through which the anesthesia is administered.

United States Patent Martinez-Manzor Dec. 25, 1973 CATHETER 3,358,68412/1967 Marshall l28/2l4.4

3,506,007 4 I970 H k' Inventor: Manuel Marlinel'Manm" 9755 3,380,4484i1968 et al. l28/215 S.W. 304th St., Homestead, Fla.

Primary Exammer-Dalton L. Truluck [22] Filed: July 24, 19 Attorney.lohnCyril Malloy [21] Appl. No.: 274,438

[57] ABSTRACT [52] Cl 128/215 128/221 128/347 For use in administeringcontinual spinal anesthesia, a A61m Catheter for longitudinal movementwithin the lumen N! d 0 Search of a relatively large needle used to pp hj 128/214 348 about to the spinal column to the end of the catheter,

a thin needle with a through opening is secured and a v [56] ReferencesC'ted stylet is provided in the catheter to advance the small UNITEDSTATES PATENTS needle relative to the large needle to pierce the wall of3,584,624 6/1971 DeCiutiis 128/2144 the spinal column in a relativelyfine opening through 2.828.744 4/1958 Hirsch et al. which the anesthesiais administered. 2.512.569 6/1950 Saffir 3,l8l,336 5/l965 Schofield 128221 x 5 Claims, 4 Drawing Figures CATHETER FIELD OF THE INVENTION Thisinvention relates to continuous spinal anesthesia; and, moreparticularly, this invention relates to an improved needle carryingcatheter for use in piercing the spinal column wall and through whichanesthesia is to be introduced as required into the column of the spinethrough a relatively small opening.

BACKGROUND OF THE INVENTION In the past, it has been learned andsubsequently widely recognized that there are advantages to continualspinal anesthesia in that the response to the introduction of anesthesiadirectly into the spinal column can produce more precise results andcontrol. Albeit recognized however, as a practical matter, actualapplication of the procedure has been limited because it has heretoforebeen difficult to pass a needle through the back ofa patient to theexact depth required for the procedure and to introduce the anesthesiathrough an opening small enough so that there are not attendant sideeffects which are very undesirable, as is explained more fullyhereinafter.

OBJECTS OF THIS INVENTION It is an object of this invention to providean improved catheter which carries on its end a small needle and meansto advance it relative to a larger needle, after the tip of the largerneedle has been prepositioned near the spinal column, so that on beingadvanced, the small needle will pierce the spinal column wall in a fineopening sufficient for introducing anesthesia but not so large as tocause injury to the spinal wall and attendant difficulties describedherein.

In accordance with this general object and purpose, the instantinvention will now be described with reference to the accompanyingdrawings in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the improvedcatheter;

FIG. 2 is a diagrammatic view of the first step in the process ofintroducing a large needle into the spine area;

FIG. 3 is a view in cross section-illustrating the use of the catheterof FIG. 1 and details of its construction; and

FIG. 4 is a view of the spinal area in cross section illustrated in theaffected area of the operation in which the improved catheter isemployed.

DETAILED DESCRIPTION OF THE INVENTION Continuous spinal anesthesia is arecognized, accepted and highly effective technique. This inventionrelates to an improved catheter for use in administering continuousspinal anesthesia. Generally, to perform the task, the anesthesicsolution is introduced directly into the dura mater 8 and arachnoidusing the improved catheter, to be described, which carries a relativelysmall needle 19 to pierce the dura wall 21. The wall is pierced by thesmaller needle after the extradural space 10 has been reached by alarger needle 12 by advancing the smaller needle carried by thecatheter. This is done in the following manner.

First, an appropriate interspinous vertebral space is selected; thesurrounding skin is scrubbed with an antiseptic solution anddried-completely;.and anesthesiaof the skin and soft tissues performed.The extradural space 10 is reached with a straight relatively largeneedle 12, preferably about 15 gauge, with a stylet in place. To theextent possible the bevel 13 of the needle is presented in longitudinalposition, for an easier pass through the skin and supra-spinous andinterspinous ligaments 14. When the characteristic major resistance ofthe flavum ligament 15, between the extra dura l0 and the zone 14 isperceived, the stylet, not shown, is removed and the distal end of thebig needle is connected to a specially treated, very sensitive, small, 2cc. syringe of glass filled with air, not shown.

The extradural space 10 on the proximal side of the flavum ligament 15is reached in the following manner. The needle 12 is very gentlyadvanced or introduced while with the other hand an effort is made toforce the penetration of the air in the syringe through the needle. Theintroduction of air will be unsuccessful until there occurs thepenetration of the needle through the favum ligament 15 and penetrationbegins into the extradural space 10. This will be recognized because,when the extradural space is reached, there will be a sudden lack ofresistance which is characteristic of this area contrasting to theresistance offered by the flavum ligament. The lack of resistanceconfirms that the extradural space has been reached. It is alsoconfirmed because, when the extradural space is reached, the air of thesyringe is introduced easily and rapidly and, simultaneously, thereoccurs a sudden inversion of the resistance against removal of the bigneedle. This is sometimes referred to as the double inverted resistancesign; in other words, the resistance given by the flavum ligament 15 isovercome and the negative pressure which characterizes the penetrationto the extradural space is sensed.

As shown in FIG. 2, once the extradural space-10 is reached by the tipof the 12, the improved catheter 17, shownin FIG. 1 and to be describedhereinafter, is introduced through the lumen 18 of the needle 12, with astylet 16, see FIG. 3, in place in the catheter 17. A firm and quickpressure is then applied to' the catheter 17 by means of the stylet 16which will cause a small needle 19 on the end of the catheter topenetrate the dura wall 21 and enter the dura mater 8 and arachnoid,reaching the subarachnoid space. Thereafter, the stylet 16 is removed.Then, a syringe is connected to the distal end of the needle carryingcatheter and a gentle suction is made until the CEF, or spinal fluid, isobtained, confirming the location of the tip of the small needle. Theanesthetic solution, which is ready in another syringe, may then beintroduced directly into the dura through the catheter in intermittentinjections of the anesthetic solution any time it will be needed duringthe surgical procedure.

It will be helpful to refer to FIG. 3 at this juncture in summary of theprocedure. The extradural space 10 between the flavum ligament 15 andthe dura wall 21 is reached by a relatively big needle 12; and thelocation of the tip or bevel 13 of the big needle is sensed in themanner described above. The catheter 17 is inserted through the column18 of the needle 12 and the wall 21 of the dura is penetrated by a smallneedle 19 fixed on the tip 20 of the catheter. A preferred embodiment ofthe small needle carrying catheter will now be-more FIG. 1.

The catheter 17 is composed of a plastic catheter tube 31 of suitablelength, which may be similar to a urethral catheter in consistence andcalibration and of about 20 gauge. To the tip 20 of the catheter tube31', a thin needle 19 of about 25 gauge is secured with the needleextending beyond the tube end about 0.5 centimeter, which correspondsfor the purposes described above to the extradural and dura space crosssectional dimension and with the catheter and needle being sized so asto be able to pass through the column of the big needle, which ispreferably gauge.

Means are provided to secure the smaller needle 19 to the tube; in theembodiment shown the means are as follows. In the plastic wall 31 at thetip of the catheter the surface of the proximal end 33 of the needle 19is provided with a key surface or pattern in relief 33 to join it to thetube, i.e., the needle is embedded in the tube wall. It will be seenthat the lumen 37 of the needle is characterized by converging sidewalls 39 to the distal end 41, which has an opening or mouth 43.

In use, through the center or column 45 of the catheter 17 the stylet 16is passed; it has a terminal end of a dimension greater than the mouth43 of the needle, but less than the inside diamter of the catheter tube,so that, when a longitudinally directed force is applied to the stylet,its leading edge will bear against the inside wall 37 of the needle foruse in driving the relatively small needle 19 through the dura wall andinto the dura mater.

It is thus seen that the above described needle carrying catheterprovides a means for introducing anesthetic solution into the durathrough a small opening relative to that which'would be made if the bigneedle were advance through the dura wall, which heretofore, when donehas been attendant with great disadvantage because of an increase in therate of postanesthesia sequalae from the relatively large perforation ofthe dura wall, dura mater and arachnoid. Because of the relatively largeperforation caused by a large needle, in the past, direct introductionof anesthesic solution directly into the dura has been limited to arelatively small number of patients denying to others the recognizedbenefits of continuous spinal anesthesia introduced directly into thedura which has been widely recognized tohave special advantages but forthe injury to the dura wall, etc., as explained above. In summary, thisinvention provides a catheter for subarachnoid anesthesia adopted forwide application in surgery. it will be seen that the catheter comprisesa tubular length of plastic material of a diameter small enough to bepassed through a larger needle of appropriate size for passage throughthe skin and supraspinous and interspinous ligaments, including theflavum ligament, which catheter has fixed to its leading end a thinneedle which is used to extend through the mouth of the larger needleand is used to pierce the dura wall in a small perforation when advancedusing a stylet, or introducer, sized for longitudinal movement ofadvance through the catheter to bear against the inside wall of therelatively small needle to advance it and the catheter and penetrate thedura wall, which stylet can then be removed for the introduction ofanesthetic solution directly into the dura or subarachnoid space throughthe column of the catheter. In the preferred embodiment means areprovided on the inner end 51 of the stylet 16 to coact with the wall ofthe needle. The means of the embodiment shown are simply the inner endof the stylet being sized so as not to pass through the opening of thesmall needle but rather to bear against the walls which converge to thetip to apply an advancement force. Other types of mutuallyintercooperating means may optionally be provided to interconnect thestylet and the catheter. Also, the outer end 61 of the catheter styletmay be provided with means 63 to aid in advancing the catheter, thepreferred embodiment including a plastic body 65 having an enlargedouter end and a somewhat smaller end in which the outer end of thestylet is captivated by suitable means.

What is claimed is:

l. A spinal anethesia administering apparatus comprising in combination,a first big needle defining a lumen and a catheter sized forlongitudinal movement removable received in the lumen of said bigneedle, said catheter including, a tubular length having a first endzone and a second end zone and of a diameter smaller than the lumen ofthe big needle,

a thin needle portion on the first end zone of said tubular lengthhaving a through passageway and a distal end portion having a tissuewall piercing tip and a proximal end portion and with said throughpassageway being in fluid transmitting engagement with said tubularlength,

an elongated stylet having a first end and a second end and with saidfirst end in said tubular length and with said second end being exteriorof said tubular length, and said stylet being of a length greater thansaid tubular length and being sized for longitudinal coaxial movement inthe tubular length and being sized less than said through opening insaid thin needle portion, and mutually interco-operating means on thefirst end of the stylet and said thin needle for applying a longitudinalforce to advance the thin needle and tubular length relative to the bigneedle after said big needle has been utilized to penetrate to apredetermined depth for a second stage of penetration by said thinneedle, whereupon the stylet may be removed from said combination andmaterial be injected through said tubular length and thin needle.

2. The combination as set forth in claim 1 wherein the interco-operatingmeans on the first end of the stylet and said thin needle comprise wallsincluded in said thin needle converging to a constricted opening at thedistal end, said opening being of a diameter greater than the diameterof the first end of said stylet and the diameter of said stylet beingless than the span between the walls of said thin needle at its proximalend to bear against the wall of the needle for advancing movement of thecatheter relative to the big needle when longitudinal force is appliedto the stylet.

3. The catheter as set forth in claim 1 wherein the catheter is of about20 gauge size, the thin needle is of about 25 gauge size and thelongitudinal dimension of the small needle is about 0.5cm.

4. The catheter as set forth in claim 1 wherein means are providedsecuring the proximal end of the thin needle to the first end zone ofthe tubular length and said means comprise an annular recess in thefirst end zone of said tubular length and said end zone is of plasticmaterial and a pattern in relief on the proximal end of the needle isprovided and said pattern is disposed within said recess and imbedded inthe plastic material of said tubular length, with said pattern in reliefkeying the needle and tubular length together as a unitary piece.

than the span between the wall of said thin needle at its proximal endto nest between the walls and thin needle ends and to bear against theneedle for advancing movement when longitudinal force is applied to thestyend of a diameter greater than the diameter of the first 5 let.

end of said stylet and the diameter of said stylet is less

1. A spinal anethesia administering apparatus comprising in combination,a first big needle defining a lumen and a catheter sized forlongitudinal movement removable received in the lumen of said bigneedle, said catheter including, a tubular length having a first endzone and a second end zone and of a diameter smaller than the lumen ofthe big needle, a thin needle portion on the first end zone of saidtubular length having a through passageway and a distal end portionhaving a tissue wall piercing tip and a proximal end portion and withsaid through passageway being in fluid transmitting engagement with saidtubular length, an elongated stylet having a first end and a second endand with said first end in said tubular length and with said second endbeing exterior of said tubular length, and said stylet being of a lengthgreater than said tubular length and being sized for longitudinalcoaxial movement in the tubular length and being sized less than saidthrough opening in said thin needle portion, and mutuallyinter-co-operating means on the first end of the stylet and said thinneedle for applying a longitudinal force to advance the thin needle andtubular length relative to the big needle after said big needle has beenutilized to penetrate to a predetermined depth for a second stage ofpenetration by said thin needle, whereupon the stylet may be removedfrom said combination and material be injected through said tubularlength and thin needle.
 2. The combination as set forth in claim 1wherein the interco-operating means on the first end of the stylet andsaid thin needle comprise walls included in said thin needle convergingto a constricted opening at the distal end, said opening being of adiameter greater than the diameter of the first end of said stylet andthe diameter of said stylet being less than the span between the wallsof said thin needle at its proximal end to bear against the wall of theneedle for advancing movement of the catheter relative to the big needlewhen longitudinal force is applied to the stylet.
 3. The catheter as setforth in claim 1 wherein the catheter is of about 20 gauge size, thethin needle is of about 25 gauge size and the longitudinal dimension ofthe small needle is about 0.5cm.
 4. The catheter as set forth in claim 1wherein means are provided securing the proximal end of the thin needleto the first end zone of the tubular length and said means comprise anannular recess in the first end zone of said tubular length and said endzone is of plastic material and a pattern in relief on the proximal endof the needle is provided and said pattern is disposed within saidrecess and imbedded in the plastic material of said tubular length, withsaid pattern in relief keying the needle and tubular length together asa unitary piece.
 5. The combination as set forth in claim 4 wherein theintercooperating means on the inner end of the stylet and cathetercomprises walls included in said thin needle converging to a constrictedopening at the distal end of a diameter greater than the diameter of thefirst end of said stylet and the diameter of said stylet is less thanthe span between the wall of said thin needle at its proximal end tonest between the walls and thin needle ends and to bear against theneedle for advancing movement when longitudinal force is applied to thestylet.